Carbon-carbon composite brake discs used in the aerospace industry typically have metal inserts attached to them. Specifically, the metal inserts are attached to slots in the interior times of the brake discs (rotors or stators). Those slots function to facilitate the transmission of torque to the brake discs. The metal inserts for stator serve to provide a surface that will transmit torque from the torque tube of the axle to the brake disc without crashing the face of the carbon-carbon composite material. Rotor inserts are used as the media to transmit toque form the wheel drive key interface to the brake discs. The metal inserts—typically held in place by rivets, adhesive, etc.—serve this purpose. However, they are relatively expensive additions to the brake discs. Labor is expended drilling holes for and attaching the inserts. Damage sometimes occurs to the carbon-carbon brake disc during installation or removal of rivets. Also, the inserts add significant weight to the brake assembly.
U.S. Pat. No. 5,273,140 describes a brake disc annular drive insert which comprises a generally cylindrical member with radially extending flanges at opposite axial, ends thereof. The drive insert includes a generally cylindrical body having an opening at one side thereof which extends diametrically into the body and terminates at a point between the center of revolution of the body and an outer surface of the body. The opening in the body extends to an inner surface of the body to provide a generally rectangular opening for receiving a spline of a torque tube. The drive insert is typically made of steel. The flanges of the drive insert may comprise either generally annular flanges shaped complementary with the generally cylindrical body and or may be truncated at a side opposite the opening in the body.
U.S. 2007/0175709 describes brake disc drive inserts for use in carbon-carbon composite brake discs. A rotatable brake disc annular drive insert includes a cylindrical steel body having one side of the body truncated to provide an insert opening which extends axially through the body. The insert opening extends into the body along a diameter of the body and the insert opening terminates at a radially extending surface located between the revolutional center of the body and an outer surface of the body. End flanges extend radially outwardly from the outer surface of the body to provide for axial positioning of the drive insert relative to a brake disc. The insert opening has a lining comprising carbon-carbon composite material. This low friction carbon-carbon composite material bed that is positioned between the steel insert component and the torque tube spline location provides significantly lower friction and enables significantly greater disc clamping and brake torque.
Other prior art of interest includes: U.S. 2007/0235126 A1, entitled BONDING OF CARBON-CARBON COMPOSITES USING TITANIUM CARBIDE; U.S. 2007/0235123 A1, entitled APPARATUS AND METHODS FOR BONDING CARBON-CARBON COMPOSITES THROUGH A REACTANT LAYER; copending application Ser. No. 11/730,373, entitled BONDING OF CARBON FIBERS TO METAL INSERTS FOR USE IN COMPOSITES; and U.S. 2007/0193836 A1, entitled METHOD AND BRAKE DISC WITH COMPOSITE INSERT MEMBER.